Reliability of Measurements Obtained With a Modified Functional

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					                            Reliability of Measurements Obtained
                            With a Modified Functional Reach
                            Test in Subjects With Spinal
                            Cord Injury
                                  Background and Purpose. The primary purpose of this study was to
                                  determine whether the Functional Reach Test (FRT) could be modi-
                                  fied to provide reliable measurements of sitting balance. A secondary
                                  purpose was to determine whether the test could be used to measure
                                  differences among levels of spinal cord injury. Subiects. Thirty male
                                  subjects with spinal cord injuries were divided into three groups based
                                  on injury type. Group 1 consisted of subjects with C5-6 tetraplegia,
                                  group 2 consisted of subjects with T1-4 paraplegia, and group 3
                                  consisted of subjects with T10-12 paraplegia. Methods. Subjects sat on
                                  similar mat tables (tables varied based on what was available at a given
                                  clinic) against the same backboard, set at 80 degrees. During two
                                  sessions, forward reach was measured with a yardstick, with a 10-minute
                                  break between sessions. Results. Intraclass correlation coefficients (3,2)
                                  were high and varied from .85 to .94. Post hoc testing revealed that
                                  differences occurred between groups 1 and 3 and groups 2 and 3, but
                                  not between groups 1 and 2. Conclusion and Discussion. Test-retest
                                  reliability was high with modification of the FRT with a single rater.
                                  The measurements reflected differences among levels of lesion. Fur-
                                  ther study is needed to determine normal values for all levels of lesion,
                                  relationships to functional outcomes, and effects of equipment on
                                  sitting balance. The modified FRT appears to provide reliable mea-
                                  surements of sitting balance in nonstanding persons with spinal cord
                                  injuries. [Lynch SM, Leahy P, Barker SP. Reliability of measurements
                                  obtained with a modified Functional Reach Test in subjects with spinal
                                  cord injury. Phys Ther. 1998;78:128-133.1

Key Words: Measurement, Reliability, Sitting balance, Spinal cord injuly.
Suzanne M Lynch

Susan P Barker

Ms LeaIiy died October 9. 1995

                                                              Physical Therapy   . Volume 78 . Number 2 . February 1998
            alance has been studied in various ways: by                       impairments, including persons with spinal cord injury

B           recording biomechanical descriptions of bal-
            ance reactions,'-4 by examining physiological
            components of b a l a n ~ e , ~ - ~ by investigating
changes in the ability of a person to balance across the
life ~ p a n . ~ J OThese studies provide a basis for under-

                                                                              The Functional Reach Test (FRT)Z0 can be used to
                                                                              measure standing balance. In our view, the FRT is fast
                                                                              and easy to use. A study using the FRT with 217 elderly
standing human performance. Often, the measurements                           male veterans (aged 70-104 years) demonstrated that
obtained. in research settings are not practical for rou-                     the test provides highly reliable measurements of bal-
tine clinical application.                                                    ance and can be used to predict the risk of falling.g1The
                                                                              FRT also can be used to estimate physical frailty22 and to
Most studies of balance have been performed with                              demonstrate change in response to treatment.Z3 In the
subjects in the standing position, but studies of sitting                     study by Weiner et al,Z3 28 inpatient male veterans were
balance have also been reported.14-l7 Most studies of                         tested every 4 weeks during a regular physical therapy
sitting balance have used instrumentation similar to that                     program, and increases in functional reach and other
used for studies of standing balance.14J5 Some balance                        mobility measures were documented. No control was
tests that are less dependent on instrumentation have                         placed on the therapy received. Studies of FRT have also
been introduced, but these measures are designed for                          demonstrated strong reliability and ~alidity.2~-z3    The
persons who can ambulate.18J9Only a few tests exist for                       FRT, therefore, possesses attributes that can make it a
clinical balance assessment of nonstanding individuals.                       meaningful and accessible test.
One such test is the Seated Posture Control Measure,l"17
which is designed to document a child's posture in his or                     Measures that can be used to predict outcomes regard-
her seating system and to assess his or her ability to                        ing the balance of patients with SCI are not available.
function. Unfortunately, the test is quite long (36 items)                    Therapists cannot be certain that prescribed wheelchairs
and may not be generalizable to persons with a variety of                     or cushions provide patients with the most stable posi-

SM Lynch, PT, NCS, is Staff Physical Therapist, Brain Injury Rehabilitation Unit, St Mary's Hospital, Rochester, NY. She was Clinical Specialist,
Spinal Cord Injury, Magee Rehabilitation Hospital, Philadelphia, Pa, at the time of this study. This study was completed in partial fulfillment of
Ms Lynch's Master of Science degree in neurologic physical therapy at Philadelphia College of Pharmacy and Science, Philadelphia, Pa. Address
all correspondence to Ms Lynch at 39 Havenshire Rd, Rochester, NY I4625 (USA) (

P I.eal,y, PT, NCS, was Assistant Professor, Philadelphia College of Pharmacy and Science, at the time of this study.

SP Barker, PT, NCS, is Associate Professor, Philadelphia College of Pharmacy and Science.

This study was approved by the Human Subjects Review Board of Magee Rehabilitation Hospital and Philadelphia College of Pharmacy and

This work is adapted from a platform presentation at the Combined Sections Meeting of the American Physical Therapy Association; February
8-12, 1995; Reno, Nev.

This adick was submitted Sqbtember 9, 1996, and was accepted June 20, 1997.

Physical Therapy   . Volume 7 8 . Number 2 . February 1998                                                                      Lynch et a l . 129
tions from which they can function (ie, the best bal-          and the presence of musculoskeletal deformities in the
ance). Defining positions that are stable and the effects      upper extremity used in reaching were examined at the
of equipment on stability would be helpful because             time of the testing. The presence of inadequate muscle
persons with paralysis are challenged to maintain their        force to maintain shoulder flexion during reaching (as
balance during a variety of functional activities.             measured by a break test of the shoulder flexors),
                                                               inadequate range of motion, or musculoskeletal defor-
For the purposes of our study, we defined sitting balance      mity meant elimination from the study. Spasticity, a
as the ability of a person to maintain control over            common sequela in persons with SCI, was not part of the
upright posture during forward reach without stabiliza-        inclusion or exclusion criteria. Spasticity was not mea-
tion. Any reaching task will be a challenge to upright         sured in any subjects.
control for persons with partial or complete paralysis of
the trunk and arms. The primary purpose of our study           Instrumentation
was to determine whether the FRT could be modified for         A yardstick was attached horizontally to a wall by Vel-
a group of individuals with SCI to provide reliable            cro@* or tape. The method of attachment varied,
measurements of sitting balance. A secondary purpose           depending on the site of data collection. According to
was to determine whether the modified FRT could                Duncan et         the method used to attach the yardstick
measure differences in functional reach among different        is not crucial. All subjects sat on a narrow mat table or a
levels of SCI.                                                 padded weight bench, which were of similar width
                                                               (about 61 cm [24 in]). The same backboard was used and
Method                                                         kept at the same angle of 80 degrees for all subjects. This
                                                               angle allowed all subjects to sit back and relax between
 Subjects                                                      trials. The backboard used in this study is also typically
Thirty male subjects participated in this study. The           used for supporting sitting activities during rehabilita-
 subjects were between 18 and 45 years of age (X=30.8,         tion of patients with SCI (Figure).
 SD=7.2). Subjects were placed in groups based solely on
 level of injury. All subjects had complete lesions accord-    Procedure
 ing to the American Spinal Injury Association's (ASIA)        Informed consent was obtained once subjects were
 Impairment S ~ a l e . 2 ~ lesions, therefore, were classi-
                        The                                    determined to be eligible for the study. The procedure
fied as either ASIA A or ASIA B, because both classifica-      for the collection of data closely followed the procedure
 tions are for complete motor injuries. The difference         described by Duncan et al.2O Once each subject was
 between the categories is in sensation. There is no           positioned on the mat table, the yardstick was placed
 sensation below the level of the lesion in ASIA A lesions,    along the subject's shoulder at the level of the acromion.
 but sensation can be partially spared in ASIA B lesions.      Subjects sat in the same position for each trial. Their
We chose these type categories of lesions to ensure that       hips, knees, and ankles were positioned with 90 degrees
 there would be no lower-extremity motor function to           of flexion, and there was 5.08 cm (2 in) of clearance
 allow the subject to weight bear on the feet when             between the popliteal fossa and the mat table. Foot
 reaching forward in sitting. All subjects were recruited      support was provided, if necessary, with a rubber floor
 from the following sources: scheduled medical appoint-        mat to ensure proper sitting position. The backboard
 ments for Magee Rehabilitation Hospital's (Philadel-          was placed behind each subject for support (Figure).
 phia, Pa) SCI follow-up system, teams that participated
 in wheelchair sports tournaments, and persons readmit-        Initial reach was measured with each subject resting
 ted to Magee Rehabilitation Hospital for intensive reha-      against the backboard with an upper-extremity flexed to
 bilitation. All subjects were seen at least 1 month after     90 degrees. The anatomical landmark used to measure
 completion of their initial phase of rehabilitation. Sub-     reach was the ulnar styloid process. Because the subjects
jects were selected based on their SCI diagnosis and           with tetraplegia in our study could not make a fist, this
 assigned to one of three groups: group 1 (n=10) con-          landmark was used instead of the third metacarpal,
 sisted of subjects with C5-6 tetraplegia, group 2 (n=10)      which was used in the original studies of FRT.20-23 The
 consisted of subjects with T1-4 paraplegia, and group 3       ulnar styloid process is a prominent landmark and was
  (n=10) consisted of subjects with T10-12 paraplegia.         proximal enough to allow accurate measurements to be
                                                               taken for all subjects. Subjects used the nonreaching
To be included in our study, subjects had to be able to sit    upper extremity for counterbalance only (eg, no weight
independently of a seating system with only a backboard        bearing or holding on was allowed). The subjects were
for support. The subjects' upper extremities had to be         guarded for safety, and the trial was repeated if the
without deformities, and each subject had to be able to        subject required assistance to recover to the backboard.
assume and maintain 90 degrees of shoulder flexion.
Muscle force (manual muscle testing), range of motion,
                                                               'Velcro USA Inc, 406 Brown Ave, Manchester, NH 03108.

130 . Lynch et al                                                        Physical Therapy. Volume 7 8 . Number 2       . February 1998
Two sites were used for data collection. Limitations of
                                                                                           I                     *r
the physical facilities at one of the data collection
locations necessitated that all 8 subjects who were tested
there use their left upper extremity. The remaining 22
subjects who were tested at the other facility used their
right upper extremity. All methods were otherwise the
same between the sites.
                                                                                   a                       .I.        r
Each subject had two practice trials of maximal forward
reach, followed by three trials during which data were                                     4                     9 '

collected. The mean of these three trials was recorded.                                                          3                       <

Following the initial three trials, each subject left the
testing area for 10 minutes and then returned to
undergo repeated testing using the same procedure. A
single rater (SML) collected all data for this study.

Data Analysis
Test-retest reliability was studied using the intraclass
correlation coefficient (ICC[3,2]) because there was a
single rater." Calculations were performed using a
spreadsheet software package.t Because a secondary
purpose of our study was to determine whether the
modified FRT could measure differences among levels
of lesion, a one-way analysis of variance (ANOVA) was
used to test for differences among the means for reach
in the three groups. A Newman-Keuls test was used to
discern differences among group means and to ensure
that Type I error was minirni~ed.?~                                              Figure.
                                                                                 Subject demonstrating positioning with backboard for data collection.
Mean reach data for the subjects are presented in the
Table. The results indicated that the reliability of mea-                        Discussion
suremen1.s obtained with the modified FRT was very                               Forward reach in a sitting position can be measured
strong. The ICCs for test-retest reliability of measure-                         reliably via a ruler attached to a wall alongside a patient
ments of average reach length were .94 for group 1, .85                          with SCI. The modified FRT achieved ICCs for test-retest
for group 2, and .93 for group 3. There were no                                  reliability similar to those documented in the original
differences between the subjects who used their right                                                  ~-~"
                                                                                 FRT s t u d i e ~ . ~ Generalizability of test-retest reliability
upper extremity and the subjects who used their left                             is weak because only one rater was available for data
upper extremity to perform the reaches.                                          collection. Further study using an interrater design may
                                                                                 allow inferences to be generalized to a greater number
The modified FRT was also tested for its ability to                              of situations.
distinguish level of lesion. Mean maximal reach was 14.7
cm (SD-7.6, range=3.3-27.4) for group 1, 15.5 cm                                 The modified FRT appears to be useful for determining
(SD=4.3, range=7.6-21.3) for group 2, and 22.9 cm                                differences in reach among different levels of lesion in
(SD=5.6, range= 14.7-29.2) for group 3. A one-way                                persons with SCI. The modified FRT measured differ-
ANOVA was used to determine that subjects with lower                             ences in reach between groups 1 and 3 and groups 2 and
levels of lesion had a longer reach compared with                                3. There was no difference in the ability to reach
subjects with higher levels of lesion. The Neuman-Keuls                          between groups 1 and 2, but mean reach was greater in
test demonstrated that reach differed only between                               group 3 compared with groups 1 and 2. This finding
groups 1 and 3 and groups 2 and 3. There was no                                  appears to be reasonable because people with lower
difference in reach between groups 1 and 2.                                      levels of paraplegia tend to have greater functional
                                                                                 capabilities than people with higher levels of lesion do.
                                                                                 The subjects in group 3 had abdominal and back exten-
                                                                                 sor muscles that were unaffected by their SCI, which
                                                                                 apparently gave them a greater advantage in movement
t Microsoft Excel 5.0, hficrosoft C:orp, One Microsort Way, Redmond, WA 98052.

Physical Therapy Volume 78 . Number 2          . February   1998                                                                     Lynchetal. 131
Table                                                                       patients are challenged appropriately by a test, and
Maximal Functional Reach
                                                                            poorer performances occur when patients believe that
                                                                            the test has no meaning for their problem. Face validity
                                             Maximal                        appears to be present in the modified FRT because
                 Subject                     Functional
                 No."                        Reach ( ~ m ) ~                subjects felt the challenge to their stability and had to
                                                                            make great effort not to fail or a fall would occur.
                  1                           14.10 (5.55)
                  2                            8.48 (3.34)                  Future research is needed to obtain evidence that the
                  3                           14.61 (5.75)
                  4                           27.53 (1 0.84)                modified FRT can be used to predict future outcomes
                  5                           19.91 (7.84)                  (predictive validity) or current balance status. We believe
                  6                           22.12 (8.71)                  that the modified FRT should be compared with mea-
                  7                            3.40 (1.34)                  sures of established criterion-related validity. Strength-
                  8                           12.70 (5.00)                  ening validity may demonstrate that the modified FRT is
                  9                            2.54 (3.21)
                 10                           15.04 (5.92)
                                                                            a proper method to answer clinical or research
                 11                           17.78 (7.00)                  questions.
                 12                           15.77 (6.21)
                 13                            7.62 (3.00)                  Studies using the modified FRT would improve its
                 14                           20.32 (8.00)                  usefulness. Because patients with SCI sit on different
                 15                           2 1.39 (8.42)
                 16                           1 1.63 (4.58)                 support surfaces (cushions and wheelchairs), compari-
                 17                           12.93 (5.09)                  sons could be made only among different products.
                 18                           17.35 (6.83)                  Measurement of functional reach may cause clinicians to
                 19                           12.80 (5.04)                  prescribe equipment based on its effects on sitting
                 20                           17.48 (6.88)                  balance.
                 21                           29.12 (1 1.46)
                 22                           27.3 1 (10.75)
                 23                           19.91 (7.84)                  Conclusion
                 24                           24.03 (9.46)                  This study examined the use of the FRT for a population
                 25                           17.15 (6.75)                  that cannot stand: persons with complete SCI. The
                 26                           28.37 (1 1.17)                modified FRT can become a highly useful test because it
                 27                           28.37 (1 1.17)
                 28                           23.93 (9.42)                  is easy and fast to perform and adaptable to many
                 29                           15.24 (6.00)                  environments. The purpose of this study was to test
                 30                           14.71 (5.79)                  whether the FRT could provide reliable measurements
"Group 1 (C.5-6 tetreplegia): subjects 1-10; group 2 ( T l 4 paraplegia):
                                                                            in persons who are unable to stand. Before the measure-
subjects 11-20; group 3 (TlG12 paraplegia): subjects 21-30.                 ments can be shown to be useful, research on their
"Measurements in inches shown in parentheses.                               validity is needed.

The modified FRT did not appear to detect differences                       1 Kirby RL, Price NA, MacLeod DA. The influence of foot position on
between the subjects with tetraplegia (group 1) and the                     standing balance. J Biomech. 1987;20:423-427.
subjects with higher levels of paraplegia (group 2).                        2 Mahar RK, Kirby RL, MacLeod DA. Simulated leg-length discrep
Although the subjects with higher levels of paraplegia                      ancy: its effect on mean center of pressure position and postural sway.
had more unaffected muscles than the subjects with                          Arch Phys Med Rehabil. 1985;6:822-824.
tetraplegia did, reach outcomes were similar. Further                       3 Nasher LM, Cordo PI. Relation of automatic postural responses and
study is needed.                                                            reaction-time voluntary movement of human leg muscles. Exp Brain
                                                                            Res. 1981;43:395-425.
Although our study indicates that reliability exists for                    4 Alexander NB, Shepard N. Gu hlJ, Schultz A. Postural control in
measurements obtained with the modified FRT, more                           young and elderly subjects when stance is perturbed: kinematics.
research is needed to establish validity. Face validity is                  J Gerontol. 1992;47:M79-M87,
the assessment of how well a test appears to measure                        5 Diener HC, Horak FB, Nasher LM. Influences of stimulus parameters
something specific. In our study, subjects with varying                     on human postural responses. J Neurqhysiol. 1988;59:1888-1905.
amounts of paralysis were asked to reach forward and                        6 Dichgans J, Diener HC. The contribution of vestibulo-spinal mech-
move without any assistance from their base of support.                     anisms to the maintenance of human upright posture. Actn Otolalyngol
                                                                            (Stockh). 1989;107:338-345.
We believed that each subject had to move to the limits
of his stability without loss of balance. We contend that                   7 Magnusson M, Johansson R. Dynamic performance of vibration
it is important for a test to measure what clinicians and                   induced anterior-posterior sway during upright in normal subjects.
                                                                            Acla Ololalyngol (Stockh). 1990;llO:168-1 74.
patients believe can affect the patients' functional per-
formance. According to Campbellz6in her discussion of                       8 Hasselkus BR, Shambus GM. Aging and postural sway in women.
                                                                            J Gerontol. 1975;30:661-667.
face validity, better performances may occur when

132 . Lynch et a1                                                                     Physical Therapy . Volume 78   . Number 2 . February 1998
9 Black FO, Wall C, Rockette HE, Kitch R. Normal subject postural            18 Tinetti M. Performance-oriented assessment of mobility problems
sway during the Romberg test. Am J Ololalyngol. 1982;3:309-318.              in elderly patients. J A m Gen'alr Soc. 1986;34:119-126.
10 Fernie GR, Gryfe CI, Holliday PJ, Llewellyn A. The relationship of        19 Shumway-Cook A, Horak FB. Assessing the influence of sensory
postural sway in standing to incidence of falls in geriatric subjects. Age   interaction o n balance: suggestion from the field. Phys Ther. 1986;66:
Ageing. 1982;ll:ll-16.                                                       1548-1550.
11 Horak FB, Shupert CL, Mirka A. Components of postural dyscon-             20 Duncan PW, Weiner DK, ChandlerJ, Studenski S. Functional reach:
trol in the elderly: a review. Neurobiol Aging. 1989;10:727-738.             a new clinical measure of balance. J Gerontol. 1990;45:M192-M197.
12 Woollacott M. Postural control mechanisms in the young and old.           21 Duncan PW, Studenski S, Chandler J, Prescott B. Functional reach:
In: Duncan PW, ed. Proceedings of the APTA Fonrm on Balance; June            predictive validity in a sample of elderly male veterans. J Gerontol.
13-15, 1989; Nashville, Tenn. Alexandria, Va: American Physical Ther-        1992;47:M93-M98.
apy Association; 199023-28.
                                                                             22 Weiner DK, Duncan PW, ChandlerJ, Studenski S. Functional reach:
13 Kleiber M, Horstmann GA, Dieh V. Body sway stabilization in               a marker of physical frailty.J A m Genatr Soc. 1992;40:203-207.
human posture. Acta Otolulyngol (Stockh). 1990;110:168-174.
                                                                             23 Weiner DK, Bongiorni DR, Studenski S, et al. Does functional reach
14 McClenaghan BA. Sitting stability of selected subjects with cerebral      improve with rehabilitation? Arch Phys Med Rehabil. 1993;74:796-800.
palsy. Clin Biomech. 1989;4:213-216.
                                                                             24 Maynard FM. Intnnational Standards for Neurological and Functional
15 Reid   D T , Sochaniwskyj A, Milner M. An investigation of postural       Classification of .Spinal Cord Injuly. Chicago, Ill: American Spinal Injury
sway in sitting of normal children and children with neurological            Association; 1996:7.
disorders. Physical 6 Occupational Therapy in Pediatrics. 1991;11:19-34.
                                                                             25 Portney LG, Watkins MP. Validity of measurements. In: Foundations
16 Fife SE, Roxborough LA, Armstrong RW, et al. Development of a             of Clinical Research: Applirations lo Practice. East Norwalk, Conn: Apple-
clinical measure of postural control for assessment of adaptive seating      ton & Lange; 1993:69-85.
in children with neuromotor disabilities. Phys Ther. 1991;71:981-993.
                                                                             26 Campbell SK. Commentary on "Measurement validity in physical
17 Fife SE, Roxborough LA, Story M, et al. Reliability of the Seated         therapy research." Phys Ther. 1993;73:60-61.
Posture Control Measure. Presented at the Ninth International Seating
Symposium; February 1993; Memphis, Tenn.

Physical Therapy . Volume 78 . Number 2 . February 1998                                                                              Lynch et al   . 133

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